Image capturing optical system

ABSTRACT

This invention provides an image capturing optical system in order from an object side to an image side comprising: a first lens element with positive refractive power having a convex object-side surface; a second lens element; a third lens element; a fourth lens element with both the object-side and image-side surfaces thereof being aspheric, and the fourth lens element is made of plastic; and a fifth lens element with negative refractive power, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof, and the fifth lens element is made of plastic. By such arrangement, photosensitivity and total track length of the system can be reduced, and better image quality can be obtained.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No. 100123802 filed in Taiwan, R.O.C. on Jul. 6, 2011, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image capturing optical system, and more particularly, to a compact image capturing optical system used in electronic products.

2. Description of the Prior Art

In recent years, with the popularity of portable electronic products having photographing function, the demand of compact imaging lens system has grown. Generally, the sensor of a general photographing camera is none other than CCD (Charge Coupled Device) or CMOS device (Complementary Metal Oxide Semiconductor device). Furthermore, advances in semiconductor manufacturing technology have allowed the pixel size of sensors to be reduced and therefore lead compact imaging lens systems to higher resolution. In the meantime, the demand for better image quality is also increased.

A conventional imaging lens system with high imaging power, such as the one set forth in U.S. Pat. No. 7,365,920, generally has a front stop and four lens elements; wherein, the first and second lens elements are adhered together to form a doublet for correcting the chromatic aberration. However, this kind of arrangement has the following disadvantages. First, the degree of freedom in arranging the lens system is curtailed due to the employment of excessive number of spherical glass lenses; thus, the total track length of the system cannot be reduced easily. Second, the process of adhering glass lenses together is complicated, posing difficulties in manufacturing. Moreover, the popularity of high-class portable devices such as Smart Phone and PDA (Personal Digital Assistant) drives the rapid improvements in high resolution and image quality of the current compact imaging lens systems, conventional four lens elements systems no longer satisfy the higher level camera modules. On the other hand, a conventional image capturing lens system with five lens elements usually has the disadvantage of having an excessively long total track length, and thereby is not suitable for compact electronic devices.

Inasmuch as the foregoing, a need is continuously existed for a lens system with good image quality and moderate total track length and is suitable for applying for compact and portable electronic products.

SUMMARY OF THE INVENTION

The present invention provides an image capturing optical system comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element; a third lens element; a fourth lens element with both the object-side and image-side surfaces thereof being aspheric, and the fourth lens element is made of plastic; and a fifth lens element with negative refractive power, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof, and the fifth lens element is made of plastic; wherein a focal length of the image capturing optical system is f, a focal length of the fifth lens element is f5, and they satisfy the following relation: −5.0<f/f5<−3.0.

On the other hand, the present invention provides an image capturing optical system comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element; a fourth lens element with positive refractive power, a convex image-side surface, both the object-side and image-side surfaces thereof being aspheric, and the fourth lens element is made of plastic; and a fifth lens element with negative refractive power, a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof, and the fifth lens element is made of plastic; wherein a focal length of the image capturing optical system is f, a focal length of the fifth lens element is f5, and they satisfy the following relation: −5.0<f/f5<−3.0.

By such arrangement, photosensitivity and total track length of the system can be reduced, and better image quality can be obtained.

In the aforementioned image capturing optical system, the first lens element has positive refractive power and thereby can provide refractive power needed for the system and is favorable for reducing the total track length thereof. When the second lens element has negative refractive power, the aberration produced by the first lens element with positive refractive power can be effectively corrected. When the fourth lens element has positive refractive power, the refractive power of the first lens element can be effectively distributed for reducing the sensitivity of the system. Moreover, when the fourth lens element has positive refractive power and the fifth lens element has negative refractive power, a positive-negative telephoto structure is formed so that the back focal length of the system is favorably reduced for shortening the total track length of the system.

In the aforementioned image capturing optical system, the first lens element can be a bi-convex lens element or a meniscus lens element having a convex object-side surface and a concave image-side surface. When the first lens element is a bi-convex lens element, the refractive power of the first lens element can be strengthened for reducing the total track length of the system. When the first lens element is a convex-concave meniscus lens element, it is favorable for correcting the spherical aberration of the system. When the second lens element is a convex-concave meniscus lens element, the aberrations produced by the first lens element can be favorably corrected and the refractive power of the second lens element can be effectively controlled for correcting the aberration of the system. When the fourth lens element has a concave object-side surface and a convex image-side surface, the astigmatism can be effectively corrected and the positive refractive power of the fourth lens element can be effectively adjusted for reducing the error sensitivity of the optical lens system. When the fifth lens element has a concave object-side surface, the negative refractive power of the fifth lens element can be properly adjusted to cooperate with the fourth lens element for obtaining the telephoto effect. When the fifth lens element has a concave image-side surface, the principal point of the system can be positioned away from the image plane, and the back focal length of the system can be reduced for favorably shortening the total track length thereof and keeping the system compact. Furthermore, when at least one inflection is formed on the fifth lens element, the angle at which light projects onto the image sensor from the off-axis field can be effectively reduced so that the sensing efficiency of the image sensor can be improved and the off-axis aberration can be corrected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows an image capturing optical system in accordance with a first embodiment of the present invention.

FIG. 1B shows the aberration curves of the first embodiment of the present invention.

FIG. 2A shows an image capturing optical system in accordance with a second embodiment of the present invention.

FIG. 2B shows the aberration curves of the second embodiment of the present invention.

FIG. 3A shows an image capturing optical system in accordance with a third embodiment of the present invention.

FIG. 3B shows the aberration curves of the third embodiment of the present invention.

FIG. 4A shows an image capturing optical system in accordance with a fourth embodiment of the present invention.

FIG. 4B shows the aberration curves of the fourth embodiment of the present invention.

FIG. 5A shows an image capturing optical system in accordance with a fifth embodiment of the present invention.

FIG. 5B shows the aberration curves of the fifth embodiment of the present invention.

FIG. 6A shows an image capturing optical system in accordance with a sixth embodiment of the present invention.

FIG. 6B shows the aberration curves of the sixth embodiment of the present invention.

FIG. 7A shows an image capturing optical system in accordance with a seventh embodiment of the present invention.

FIG. 7B shows the aberration curves of the seventh embodiment of the present invention.

FIG. 8A shows an image capturing optical system in accordance with an eighth embodiment of the present invention.

FIG. 8B shows the aberration curves of the eighth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides an image capturing optical system comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element; a third lens element; a fourth lens element with both the object-side and image-side surfaces thereof being aspheric, and the fourth lens element is made of plastic; and a fifth lens element with negative refractive power, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof, and the fifth lens element is made of plastic; wherein a focal length of the image capturing optical system is f, a focal length of the fifth lens element is f5, and they satisfy the following relation: −5.0<f/f5<−3.0.

When the relation of −5.0<f/f5<−3.0 is satisfied, the fifth lens element of the present invention can be configured with stronger negative refractive power, which can effectively correct the high order aberration produced by the system for obtaining better image quality; preferably, the following relation is satisfied: −4.5<f/f5<−3.2; more preferably, the following relation is satisfied: −4.5<f/f5<−3.4.

In the aforementioned image capturing optical system, a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of the image-side surface of the second lens element is R4, and they preferably satisfy the following relation: 1.5<(R3+R4)/(R3−R4)<4.5. When the above relation is satisfied, the curvature of the second lens element is more suitable and thereby the aberration of the system can be corrected favorably.

In the aforementioned image capturing optical system, the focal length of the image capturing optical system is f, a focal length of the third lens element is f3, and they preferably satisfy the following relation: −0.5<f/f3<0.5. When the above relation is satisfied, the third lens element can effectively distribute the refractive power required for the system and thereby reduce the sensitivity of the system.

In the aforementioned image capturing optical system, a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, and they preferably satisfy the following relation: 2.5<CT4/CT5<4.5. When the above relation is satisfied, the arrangement of the thickness of the fourth lens element and the fifth lens element is more balance for keeping the compact property and is favorable for manufacturing.

In the aforementioned image capturing optical system, a curvature radius of the image-side surface of the fourth lens element is R8, the focal length of the image capturing optical system is f, and they preferably satisfy the following relation: −0.25<R8/f<−0.05. When the above relation is satisfied, appropriate positive refractive power can be obtained by the arrangement of the curvature radius of the image-side surface of the fourth lens element, and thereby the error sensitivity of the system can be favorably reduced. Also, the positive refractive power of the fourth lens element can complement with the negative refractive power of the fifth lens element for providing telephoto effect.

In the aforementioned image capturing optical system, the system further comprises a stop, an axial distance between the stop and the image-side surface of the fifth lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the fifth lens element is TD, and they preferably satisfy the following relation: 0.75<SD/TD<1.1. When the above relation is satisfied, a better balance between the properties of telecentricity and wide field of view can be favorably obtained.

In the aforementioned image capturing optical system, an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, a central thickness of the third lens element is CT3, and they preferably satisfy the following relation: 2.0<(T23+T34)/CT3<4.0. When the above relation is satisfied, the arrangement for each lens element is more suitable for manufacturing with an appropriate total track length.

In the aforementioned image capturing optical system, the system further comprises an image sensor provided on an image plane, an axial distance between the object-side surface of the first lens element and the image plane is TTL, half of a diagonal length of an effective photosensitive area of the image sensor is ImgH, and they preferably satisfy the following relation: TTL/ImgH<2.0. When the above relation is satisfied, it is favorable for keeping the system compact in order to be equipped on portable electronic products.

In the aforementioned image capturing optical system, an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, and they preferably satisfy the following relation: 30<V1−V2<42. When the above relation is satisfied, the chromatic aberration of the system can be corrected favorably.

In the aforementioned image capturing optical system, the focal length of the image capturing optical system is f, a focal length of the fourth lens element is f4, the focal length of the fifth lens element is f5, and they preferably satisfy the following relation: 5.0<|f/f4|+|f/f5|<8.0. When the above relation is satisfied, the arrangement of the refractive power of the fourth lens element and the fifth lens element is more balanced, and thereby the sensitivity of the system can be favorably reduced and the fourth lens element and the fifth lens element can complement with each other for providing telephoto effect, which can reduce the back focal length of the system.

In the aforementioned image capturing optical system, a curvature radius of the object-side surface of the fifth lens element is R9, a curvature radius of the image-side surface of the fifth lens element is R10, and they preferably satisfy the following relation: −0.8<(R9+R10)/(R9−R10)<0.4. When the above relation is satisfied, the curvature of the fifth lens element is more suitable, and thereby a fifth lens element with stronger negative refractive power can be configured for correcting the high order aberration of the system favorably.

On the other hand, the present invention provides an image capturing optical system comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element; a fourth lens element with positive refractive power, a convex image-side surface, both the object-side and image-side surfaces thereof being aspheric, and the fourth lens element is made of plastic; and a fifth lens element with negative refractive power, a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof, and the fifth lens element is made of plastic; wherein a focal length of the image capturing optical system is f, a focal length of the fifth lens element is f5, and they satisfy the following relation: −5.0<f/f5<−3.0.

When the relation of −5.0<f/f5<−3.0 is satisfied, the fifth lens element of the present invention can be configured with stronger negative refractive power, which can effectively correct the high order aberration produced by the system for obtaining better imaging quality; preferably, the following relation is satisfied: −4.5<f/f5<−3.2.

In the aforementioned image capturing optical system, a curvature radius of the image-side surface of the fourth lens element is R8, the focal length of the image capturing optical system is f, and they preferably satisfy the following relation: −0.25<R8/f<−0.05. When the above relation is satisfied, appropriate positive refractive power can be obtained by the arrangement of the curvature radius of the image-side surface of the fourth lens element, and thereby the error sensitivity of the system can be favorably reduced. Also, the positive refractive power of the fourth lens element can complement with the negative refractive power of the fifth lens element for providing telephoto effect.

In the aforementioned image capturing optical system, the focal length of the image capturing optical system is f, a focal length of the fourth lens element is f4, the focal length of the fifth lens element is f5, and they preferably satisfy the following relation: 5.0<|f/f4|+|f/f5|<8.0. When the above relation is satisfied, the arrangement of the refractive power of the fourth lens element and the fifth lens element is more balance, and thereby the sensitivity of the system can be favorably reduced and the fourth lens element and the fifth lens element can complement with each other for providing telephoto effect, which can reduce the back focal length of the system.

In the aforementioned image capturing optical system, the lens elements can be made of glass or plastic material. If the lens elements are made of glass, the freedom for distributing the refractive power of the image capturing optical system can be increased. If plastic material is adopted to produce the lens elements, the production cost will be reduced effectively. Additionally, the surfaces of the lens elements can be aspheric and easily made into non-spherical profiles, allowing more design parameter freedom which can be used to reduce aberrations and the number of the lens elements used in an optical system. Consequently, the total track length of the image capturing optical system can be effectively reduced.

In the present image capturing optical system, if a lens element has a convex surface, it means the portion of the surface in proximity to the optical axis is convex; if a lens element has a concave surface, it means the portion of the surface in proximity to the optical axis is concave.

In the present image capturing optical system, there can be at least one stop, such as a glare stop or a field stop, provided for eliminating stray light and thereby promoting image resolution thereof.

In the present image capturing optical system, the stop can be configured as a front stop or a middle-placed stop. A front stop can provide a longer distance between an exit pupil of the system and an image plane and can improve the image-sensing efficiency of an image sensor of CCD or CMOS. A middle-placed stop is favorable for enlarging the field of view of the system and thereby provides a wide field of view for the same.

Preferred embodiments of the present invention will be described in the following paragraphs by referring to the accompanying drawings.

Embodiment 1

FIG. 1A shows an image capturing optical system in accordance with the first embodiment of the present invention, and FIG. 1B shows the aberration curves of the first embodiment of the present invention. The image capturing optical system of the first embodiment of the present invention mainly comprises five lens elements, in order from an object side to an image side:

a first lens element 110 made of plastic with positive refractive power having a convex object-side surface 111 and a concave image-side surface 112, the object-side and image-side surfaces 111 and 112 thereof being aspheric;

a second lens element 120 made of plastic with negative refractive power having a convex object-side surface 121 and a concave image-side surface 122, the object-side and image-side surfaces 121 and 122 thereof being aspheric;

a third lens element 130 made of plastic with positive refractive power having a concave object-side surface 131 and a convex image-side surface 132, the object-side and image-side surfaces 131 and 132 thereof being aspheric;

a fourth lens element 140 made of plastic with positive refractive power having a concave object-side surface 141 and a convex image-side surface 142, the object-side and image-side surfaces 141 and 142 thereof being aspheric; and

a fifth lens element 150 made of plastic with negative refractive power having a concave object-side surface 151 and a concave image-side surface 152, the object-side and image-side surfaces 151 and 152 thereof being aspheric, and at least one inflection point is formed on both the object-side surface 151 and the image-side surface 152 thereof;

wherein an aperture stop 100 is disposed between the first lens element 110 and the second lens element 120;

the image capturing optical system further comprises an IR filter 160 disposed between the image-side surface 152 of the fifth lens element 150 and an image plane 171, and the IR filter 160 is made of glass and has no influence on the focal length of the image capturing optical system; the image capturing optical system further comprises an image sensor 170 provided on the image plane 171.

The detailed optical data of the first embodiment is shown in TABLE 1, and the aspheric surface data is shown in TABLE 2, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view.

TABLE 1 (Embodiment 1) f = 4.33 mm, Fno = 2.85, HFOV = 33.5 deg. Focal Surface # Curvature Radius Thickness Material Index Abbe # length 0 Object Plano Infinity 1 Lens 1   1.664200 (ASP) 0.533 Plastic 1.544 55.9 3.54 2 10.876400 (ASP) 0.050 3 Ape. Stop Plano 0.050 4 Lens 2   3.113300 (ASP) 0.250 Plastic 1.634 23.8 -6.88 5   1.759550 (ASP) 0.480 6 Lens 3 -39.859100 (ASP) 0.428 Plastic 1.544 55.9 19.74 7  -8.493500 (ASP) 0.618 8 Lens 4  -9.663100 (ASP) 0.941 Plastic 1.544 55.9 1.68 9  -0.865750 (ASP) 0.221 10 Lens 5  -1.423360 (ASP) 0.280 Plastic 1.544 55.9 -1.37 11   1.680830 (ASP) 0.500 12 IR-filter Plano 0.300 Glass 1.517 64.2 — 13 Plano 0.490 14 Image Plano — * Reference wavelength is d-line 587.6 nm

TABLE 2 Aspheric Coefficients Surface # 1 2 4 5 6 k = 8.33767E−01 −3.90332E+01 1.21872E+00 2.03126E+00 4.86797E+01 A4 = −1.58232E−02 −5.27194E−02 −2.04864E−01 −1.94118E−01 −8.09187E−02 A6 = 3.16938E−04 1.25386E−01 3.13222E−01 2.12571E−01 4.62327E−03 A8 = 1.90293E−02 1.88684E−02 −1.52843E−01 −1.99473E−01 5.20006E−02 A10 = −5.07980E−02 −1.09040E−01 −1.11414E−01 8.67946E−02 −3.08929E−02 A12 = 5.91719E−02 1.38384E−01 1.47237E−01 −7.44427E−02 2.67335E−02 A14 = −5.98706E−03 −3.21924E−02 −4.62316E−02 2.34564E−02 −6.97206E−03 Surface # 7 8 9 10 11 k = 7.54311E+00 −4.88982E+01 −3.79352E+00 −9.21378E+00 −1.71541E+01 A4 = −8.28529E−02 −8.97340E−02 −7.31056E−02 −4.01086E−02 −3.57146E−02 A6 = 1.53407E−02 1.16317E−02 2.59666E−02 3.20483E−03 4.81697E−03 A8 = −9.65766E−03 −1.94228E−02 −1.31784E−02 1.66134E−03 −8.15651E−04 A10 = 1.31648E−02 1.12452E−03 7.66627E−04 −2.30318E−04 2.65513E−05 A12 = 1.02690E−03 1.02765E−03 5.36162E−04 9.75220E−06 6.45422E−06 A14 = −2.51979E−05 −3.01649E−04 3.72636E−07 −7.38679E−07 −2.63112E−07

The equation of the aspheric surface profiles is expressed as follows:

${X(Y)} = {{\left( {Y^{2}/R} \right)/\left( {1 + {{sqrt}\left( {1 - {\left( {1 + k} \right)*\left( {Y/R} \right)^{2}}} \right)}} \right)} + {\sum\limits_{i}{({Ai})*\left( Y^{i} \right)}}}$

wherein:

X: the height of a point on the aspheric surface at a distance Y from the optical axis relative to the tangential plane at the aspheric surface vertex;

Y: the distance from the point on the curve of the aspheric surface to the optical axis;

k: the conic coefficient;

Ai: the aspheric coefficient of order i.

In the first embodiment of the present image capturing optical system, the focal length of the image capturing optical system is f, and it satisfies the following relation: f=4.33 (mm).

In the first embodiment of the present image capturing optical system, the f-number of the image capturing optical system is Fno, and it satisfies the relation: Fno=2.85.

In the first embodiment of the present image capturing optical system, half of the maximal field of view of the image capturing optical system is HFOV, and it satisfies the relation: HFOV=33.5 deg.

In the first embodiment of the present image capturing optical system, an Abbe number of the first lens element 110 is V1, an Abbe number of the second lens element 120 is V2, and they satisfy the following relation: V1−V2=32.1.

In the first embodiment of the present image capturing optical system, a central thickness of the fourth lens element 140 is CT4, a central thickness of the fifth lens element 150 is CT5, and they satisfy the following relation: CT4/CT5=3.36.

In the first embodiment of the present image capturing optical system, an axial distance between the second lens element 120 and the third lens element 130 is T23, an axial distance between the third lens element 130 and the fourth lens element 140 is T34, a central thickness of the third lens element 130 is CT3, and they satisfy the following relation: (T23+T34)/CT3=2.57.

In the first embodiment of the present image capturing optical system, a curvature radius of the object-side surface 121 of the second lens element 120 is R3, a curvature radius of the image-side surface 122 of the second lens element 120 is R4, and they satisfy the following relation: (R3+R4)/(R3−R4)=3.60.

In the first embodiment of the present image capturing optical system, a curvature radius of the object-side surface 151 of the fifth lens element 150 is R9, a curvature radius of the image-side surface 152 of the fifth lens element 150 is R10, and they satisfy the following relation: (R9+R10)/(R9−R10)=−0.08.

In the first embodiment of the present image capturing optical system, a curvature radius of the image-side surface 142 of the fourth lens element 140 is R8, the focal length of the image capturing optical system is f, and they satisfy the following relation: R8/f=−0.20.

In the first embodiment of the present image capturing optical system, the focal length of the image capturing optical system is f, a focal length of the third lens element 130 is f3, and they satisfy the following relation: f/f3=0.22.

In the first embodiment of the present image capturing optical system, the focal length of the image capturing optical system is f, a focal length of the fifth lens element 150 is f5, and they satisfy the following relation: f/f5=−3.16.

In the first embodiment of the present image capturing optical system, the focal length of the image capturing optical system is f, a focal length of the fourth lens element 140 is f4, the focal length of the fifth lens element 150 is f5, and they satisfy the following relation: |f/f4|+|f/f5|=5.73.

In the first embodiment of the present image capturing optical system, an axial distance between the aperture stop 100 and the image-side surface 152 of the fifth lens element 150 is SD, an axial distance between the object-side surface 111 of the first lens element 110 and the image-side surface 152 of the fifth lens element 150 is TD, and they satisfy the following relation: SD/TD=0.85.

In the first embodiment of the present image capturing optical system, an axial distance between the object-side surface 111 of the first lens element 110 and the image plane 171 is TTL, half of a diagonal length of an effective photosensitive area of the image sensor 170 is ImgH, and they satisfy the following relation: TTL/ImgH=1.76.

Embodiment 2

FIG. 2A shows an image capturing optical system in accordance with the second embodiment of the present invention, and FIG. 2B shows the aberration curves of the second embodiment of the present invention. The image capturing optical system of the second embodiment of the present invention mainly comprises five lens elements, in order from an object side to an image side:

a first lens element 210 made of plastic with positive refractive power having a convex object-side surface 211 and a concave image-side surface 212, the object-side and image-side surfaces 211 and 212 thereof being aspheric;

a second lens element 220 made of plastic with negative refractive power having a convex object-side surface 221 and a concave image-side surface 222, the object-side and image-side surfaces 221 and 222 thereof being aspheric;

a third lens element 230 made of plastic with positive refractive power having a convex object-side surface 231 and a convex image-side surface 232, the object-side and image-side surfaces 231 and 232 thereof being aspheric;

a fourth lens element 240 made of plastic with positive refractive power having a concave object-side surface 241 and a convex image-side surface 242, the object-side and image-side surfaces 241 and 242 thereof being aspheric; and

a fifth lens element 250 made of plastic with negative refractive power having a concave object-side surface 251 and a concave image-side surface 252, the object-side and image-side surfaces 251 and 252 thereof being aspheric, and at least one inflection point is formed on both the object-side surface 251 and the image-side surface 252 thereof;

wherein an aperture stop 200 is disposed between the first lens element 210 and the second lens element 220;

the image capturing optical system further comprises an IR filter 260 disposed between the image-side surface 252 of the fifth lens element 250 and an image plane 271, and the IR filter 260 is made of glass and has no influence on the focal length of the image capturing optical system; the image capturing optical system further comprises an image sensor 270 provided on the image plane 271.

The detailed optical data of the second embodiment is shown in TABLE 3, and the aspheric surface data is shown in TABLE 4, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view.

TABLE 3 (Embodiment 2) f = 4.35 mm, Fno = 2.85, HFOV = 33.1 deg. Focal Surface # Curvature Radius Thickness Material Index Abbe # length 0 Object Plano Infinity 1 Lens 1  1.727753 (ASP) 0.541 Plastic 1.535 56.3 3.58 2 15.933402 (ASP) 0.035 3 Ape. Stop Plano 0.080 4 Lens 2  3.249075 (ASP) 0.286 Plastic 1.650 21.4 -6.41 5  1.761559 (ASP) 0.458 6 Lens 3 24.574178 (ASP) 0.430 Plastic 1.544 55.9 11.63 7  -8.473051 (ASP) 0.620 8 Lens 4  -8.716875 (ASP) 1.184 Plastic 1.535 56.3 1.53 9  -0.781277 (ASP) 0.179 10 Lens 5  -1.067128 (ASP) 0.317 Plastic 1.535 56.3 -1.21 11   1.828325 (ASP) 0.400 12 IR-filter Plano 0.300 Glass 1.517 64.2 — 13 Plano 0.425 14 Image Plano — * Reference wavelength is d-line 587.6 nm

TABLE 4 Aspheric Coefficients Surface # 1 2 4 5 6 k = 8.62368E−01 5.03972E+00 1.34511E+00 2.07894E+00 −1.00000E+00 A4 = −1.32490E−02 −5.46477E−02 −2.06567E−01 −2.11677E−01 −7.40816E−02 A6 = 5.88593E−04 1.24941E−01 3.23760E−01 2.06880E−01 6.85023E−03 A8 = 3.42438E−02 1.21832E−01 −1.65624E−01 −2.09507E−01 5.65475E−02 A10 = −7.43772E−02 −2.35714E−01 −3.21678E−01 3.69034E−02 −3.50569E−02 A12 = 7.09448E−02 −4.32324E−01 4.45872E−01 −1.88130E−02 1.98610E−02 A14 = −7.92872E−03 8.63940E−01 −4.62328E−02 2.34558E−02 −4.60460E−03 Surface # 7 8 9 10 11 k = 9.47271E−01 2.80851E+01 −3.95160E+00 −1.03679E+01 −1.01984E+01 A4 = −8.43459E−02 −9.65180E−02 −7.62128E−02 −4.05789E−02 −3.56431E−02 A6 = 1.71494E−02 2.19387E−02 3.11470E−02 3.18188E−03 5.43609E−03 A8 = −7.09279E−03 −2.08083E−02 −1.27134E−02 1.71220E−03 −8.10968E−04 A10 = 1.30660E−02 −1.35422E−04 7.65966E−04 −2.15950E−04 2.83940E−05 A12 = 1.22688E−03 1.02710E−03 4.85624E−04 9.12256E−06 5.43291E−06 A14 = 5.57775E−05 4.81718E−05 −2.40581E−05 −1.12423E−06 −2.92442E−07

The equation of the aspheric surface profiles of the second embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the second embodiment are listed in the following TABLE 5.

TABLE 5 (Embodiment 2) f 4.35 (R9 + R10)/(R9 − R10) −0.26 Fno 2.85 R8/f −0.18 HFOV 33.1 f/f3 0.37 V1 − V2 34.9 f/f5 −3.58 CT4/CT5 3.74 |f/f4| + |f/f5| 6.43 (T23 + T34)/CT3 2.51 SD/TD 0.86 (R3 + R4)/(R3 − R4) 3.37 TTL/ImgH 1.80 Embodiment 3

FIG. 3A shows an image capturing optical system in accordance with the third embodiment of the present invention, and FIG. 3B shows the aberration curves of the third embodiment of the present invention. The image capturing optical system of the third embodiment of the present invention mainly comprises five lens elements, in order from an object side to an image side:

a first lens element 310 made of plastic with positive refractive power having a convex object-side surface 311 and a concave image-side surface 312, the object-side and image-side surfaces 311 and 312 thereof being aspheric;

a second lens element 320 made of plastic with negative refractive power having a convex object-side surface 321 and a concave image-side surface 322, the object-side and image-side surfaces 321 and 322 thereof being aspheric;

a third lens element 330 made of plastic with positive refractive power having a convex object-side surface 331 and a convex image-side surface 332, the object-side and image-side surfaces 331 and 332 thereof being aspheric;

a fourth lens element 340 made of plastic with positive refractive power having a concave object-side surface 341 and a convex image-side surface 342, the object-side and image-side surfaces 341 and 342 thereof being aspheric; and

a fifth lens element 350 made of plastic with negative refractive power having a concave object-side surface 351 and a concave image-side surface 352, the object-side and image-side surfaces 351 and 352 thereof being aspheric, and at least one inflection point is formed on both the object-side surface 351 and the image-side surface 352 thereof;

wherein an aperture stop 300 is disposed between the first lens element 310 and the second lens element 320;

the image capturing optical system further comprises an IR filter 360 disposed between the image-side surface 352 of the fifth lens element 350 and an image plane 371, and the IR filter 360 is made of glass and has no influence on the focal length of the image capturing optical system; the image capturing optical system further comprises an image sensor 370 provided on the image plane 371.

The detailed optical data of the third embodiment is shown in TABLE 6, and the aspheric surface data is shown in TABLE 7, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view.

TABLE 6 (Embodiment 3) f = 4.63 mm, Fno = 3.00, HFOV = 32.3 deg. Focal Surface # Curvature Radius Thickness Material Index Abbe # length 0 Object Plano Infinity 1 Lens 1   1.729133 (ASP) 0.540 Plastic 1.514 56.8 3.72 2 16.442005 (ASP) 0.037 3 Ape. Stop Plano 0.080 4 Lens 2   3.265483 (ASP) 0.286 Plastic 1.634 23.8 -6.50 5   1.760378 (ASP) 0.459 6 Lens 3 25.055158 (ASP) 0.430 Plastic 1.535 56.3 11.82 7  -8.400486 (ASP) 0.620 8 Lens 4  -8.665761 (ASP) 1.189 Plastic 1.535 56.3 1.53 9  -0.781227 (ASP) 0.179 10 Lens 5  -1.067010 (ASP) 0.317 Plastic 1.535 56.3 -1.21 11   1.825101 (ASP) 0.500 12 IR-filter Plano 0.300 Glass 1.517 64.2 — 13 Plano 0.512 14 Image Plano — * Reference wavelength is d-line 587.6 nm

TABLE 7 Aspheric Coefficients Surface # 1 2 4 5 6 k = 8.62415E−01 4.92768E+00 1.34600E+00 2.07884E+00 −1.00000E+00 A4 = −1.32469E−02 −5.46509E−02 −2.06564E−01 −2.11683E−01 −7.40763E−02 A6 = 5.96622E−04 1.24935E−01 3.23767E−01 2.06871E−01 6.85553E−03 A8 = 3.43119E−02 1.21815E−01 −1.65610E−01 −2.09521E−01 5.65525E−02 A10 = −7.43163E−02 −2.35931E−01 −3.21635E−01 3.68795E−02 −3.50523E−02 A12 = 7.09845E−02 −4.36056E−01 4.46849E−01 −2.03284E−02 1.98654E−02 A14 = −7.90063E−03 8.42290E−01 −3.78951E−02 2.30111E−02 −4.60460E−03 Surface # 7 8 9 10 11 k = 9.70317E−01 2.80474E+01 −3.95144E+00 −1.03720E+01 −1.02215E+01 A4 = −8.43509E−02 −9.65149E−02 −7.62173E−02 −4.05754E−02 −3.56613E−02 A6 = 1.71453E−02 2.19445E−02 3.11453E−02 3.18238E−03 5.43527E−03 A8 = −7.09585E−03 −2.08034E−02 −1.27140E−02 1.71228E−03 −8.11033E−04 A10 = 1.30637E−02 −1.32114E−04 7.65809E−04 −2.15933E−04 2.83883E−05 A12 = 1.22518E−03 1.02925E−03 4.85576E−04 9.12582E−06 5.43234E−06 A14 = 5.57775E−05 4.95682E−05 −2.40731E−05 −1.12356E−06 −2.92508E−07

The equation of the aspheric surface profiles of the third embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the third embodiment are listed in the following TABLE 8.

TABLE 8 (Embodiment 3) f 4.63 (R9 + R10)/(R9 − R10) −0.26 Fno 3.00 R8/f −0.17 HFOV 32.3 f/f3 0.39 V1 − V2 33.0 f/f5 −3.81 CT4/CT5 3.75 |f/f4| + |f/f5| 6.84 (T23 + T34)/CT3 2.51 SD/TD 0.86 (R3 + R4)/(R3 − R4) 3.34 TTL/ImgH 1.87 Embodiment 4

FIG. 4A shows an image capturing optical system in accordance with the fourth embodiment of the present invention, and FIG. 4B shows the aberration curves of the fourth embodiment of the present invention. The image capturing optical system of the fourth embodiment of the present invention mainly comprises five lens elements, in order from an object side to an image side:

a first lens element 410 made of plastic with positive refractive power having a convex object-side surface 411 and a concave image-side surface 412, the object-side and image-side surfaces 411 and 412 thereof being aspheric;

a second lens element 420 made of plastic with negative refractive power having a convex object-side surface 421 and a concave image-side surface 422, the object-side and image-side surfaces 421 and 422 thereof being aspheric;

a third lens element 430 made of plastic with positive refractive power having a concave object-side surface 431 and a convex image-side surface 432, the object-side and image-side surfaces 431 and 432 thereof being aspheric;

a fourth lens element 440 made of plastic with positive refractive power having a convex object-side surface 441 and a convex image-side surface 442, the object-side and image-side surfaces 441 and 442 thereof being aspheric; and

a fifth lens element 450 made of plastic with negative refractive power having a concave object-side surface 451 and a concave image-side surface 452, the object-side and image-side surfaces 451 and 452 thereof being aspheric, and at least one inflection point is formed on both the object-side surface 451 and the image-side surface 452 thereof;

wherein an aperture stop 400 is disposed between an imaged object and the first lens element 410;

the image capturing optical system further comprises an IR filter 460 disposed between the image-side surface 452 of the fifth lens element 450 and an image plane 471, and the IR filter 460 is made of glass and has no influence on the focal length of the image capturing optical system; the image capturing optical system further comprises an image sensor 470 provided on the image plane 471.

The detailed optical data of the fourth embodiment is shown in TABLE 9, and the aspheric surface data is shown in TABLE 10, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view.

TABLE 9 (Embodiment 4) f = 4.23 mm, Fno = 3.30, HFOV =33.4 deg. Focal Surface # Curvature Radius Thickness Material Index Abbe # length 0 Object Plano Infinity 1 Ape. Stop Plano -0.115 2 Lens 1    1.692563 (ASP) 0.526 Plastic 1.535 56.3 3.66 3   11.121373 (ASP) 0.103 4 Lens 2    3.034228 (ASP) 0.262 Plastic 1.633 23.4 -6.69 5    1.708375 (ASP) 0.504 6 Lens 3 -175.078680 (ASP) 0.412 Plastic 1.535 56.3 14.48 7   -7.417758 (ASP) 0.690 8 Lens 4   50.000000 (ASP) 0.960 Plastic 1.535 56.3 1.71 9    -0.924454 (ASP) 0.212 10 Lens 5    -0.967772 (ASP) 0.431 Plastic 1.535 56.3 -1.34 11    3.220075 (ASP) 0.400 12 IR-filter Plano 0.300 Glass 1.517 64.2 — 13 Plano 0.362 14 Image Plano — * Reference wavelength is d-line 587.6 nm

TABLE 10 Aspheric Coefficients Surface # 2 3 4 5 6 k = 8.64088E−01 −4.58599E+01 −3.38650E−02 1.98002E+00 5.00000E+01 A4 = −1.28569E−02 −5.77372E−02 −2.09549E−01 −2.03117E−01 −7.59005E−02 A6 = −1.33309E−03 1.14838E−01 3.01719E−01 2.05725E−01 5.85643E−03 A8 = 3.63338E−02 8.52022E−02 −1.76475E−01 −2.47215E−01 5.54235E−02 A10 = −8.91984E−02 −2.02564E−01 −3.33498E−01 7.33910E−02 −3.25023E−02 A12 = 7.33844E−02 −4.35565E−01 4.48465E−01 −2.21802E−02 1.99915E−02 A14 = 6.37080E−03 8.27201E−01 −2.39055E−02 1.44922E−02 −4.66865E−03 Surface # 7 8 9 10 11 k = 5.93129E+00 4.57617E+01 −3.64824E+00 −5.04303E+00 −1.80045E−01 A4 = −8.54209E−02 −9.00664E−02 −8.16794E−02 −3.60234E−02 −5.14646E−02 A6 = 1.70799E−02 2.28190E−02 3.27492E−02 3.16828E−03 5.91053E−03 A8 = −7.22990E−03 −1.62626E−02 −1.20968E−02 1.71655E−03 −7.72595E−04 A10 = 1.20566E−02 1.63212E−03 8.62941E−04 −2.13999E−04 2.83937E−05 A12 = 4.15047E−04 1.14987E−03 5.01526E−04 8.83016E−06 4.63551E−06 A14 = −5.45990E−05 −2.26131E−04 −2.03652E−05 −1.57191E−06 −4.80753E−07

The equation of the aspheric surface profiles of the fourth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the fourth embodiment are listed in the following TABLE 11.

TABLE 11 (Embodiment 4) f 4.23 (R9 + R10)/(R9 − R10) −0.54 Fno 3.30 R8/f −0.22 HFOV 33.4 f/f3 0.29 V1 − V2 32.9 f/f5 −3.15 CT4/CT5 2.23 |f/f4| + |f/f5| 5.63 (T23 + T34)/CT3 2.90 SD/TD 0.97 (R3 + R4)/(R3 − R4) 3.58 TTL/ImgH 1.77 Embodiment 5

FIG. 5A shows an image capturing optical system in accordance with the fifth embodiment of the present invention, and FIG. 5B shows the aberration curves of the fifth embodiment of the present invention. The image capturing optical system of the fifth embodiment of the present invention mainly comprises five lens elements, in order from an object side to an image side:

a first lens element 510 made of plastic with positive refractive power having a convex object-side surface 511 and a convex image-side surface 512, the object-side and image-side surfaces 511 and 512 thereof being aspheric;

a second lens element 520 made of plastic with negative refractive power having a convex object-side surface 521 and a concave image-side surface 522, the object-side and image-side surfaces 521 and 522 thereof being aspheric;

a third lens element 530 made of plastic with negative refractive power having a convex object-side surface 531 and a concave image-side surface 532, the object-side and image-side surfaces 531 and 532 thereof being aspheric;

a fourth lens element 540 made of plastic with positive refractive power having a concave object-side surface 541 and a convex image-side surface 542, the object-side and image-side surfaces 541 and 542 thereof being aspheric; and

a fifth lens element 550 made of plastic with negative refractive power having a concave object-side surface 551 and a concave image-side surface 552, the object-side and image-side surfaces 551 and 552 thereof being aspheric, and at least one inflection point is formed on both the object-side surface 551 and the image-side surface 552 thereof;

wherein an aperture stop 500 is disposed between the first lens element 510 and the second lens element 520;

the image capturing optical system further comprises an IR filter 560 disposed between the image-side surface 552 of the fifth lens element 550 and an image plane 571, and the IR filter 560 is made of glass and has no influence on the focal length of the image capturing optical system; the image capturing optical system further comprises an image sensor 570 provided on the image plane 571.

The detailed optical data of the fifth embodiment is shown in TABLE 12, and the aspheric surface data is shown in TABLE 13, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view.

TABLE 12 (Embodiment 5) f = 4.42 mm, Fno = 3.00, HFOV = 32.6 deg. Focal Surface # Curvature Radius Thickness Material Index Abbe # length 0 Object Plano Infinity 1 Lens 1   2.020480 (ASP) 0.582 Plastic 1.535 56.3 3.38 2 -15.384600 (ASP) 0.102 3 Ape. Stop Plano -0.002 4 Lens 2   5.695600 (ASP) 0.250 Plastic 1.634 23.8 -6.80 5   2.412720 (ASP) 0.583 6 Lens 3   9.990000 (ASP) 0.462 Plastic 1.634 23.8 -51.14 7   7.499900 (ASP) 0.466 8 Lens 4 -16.535300 (ASP) 0.852 Plastic 1.535 56.3 1.56 9  -0.809830 (ASP) 0.210 10 Lens 5  -1.581540 (ASP) 0.282 Plastic 1.535 56.3 -1.40 11   1.499360 (ASP) 0.500 12 IR-filter Plano 0.300 Glass 1.517 64.2 — 13 Plano 0.719 14 Image Plano — * Reference wavelength is d-line 587.6 nm

TABLE 13 Aspheric Coefficients Surface # 1 2 4 5 6 k = 7.40670E−01 −5.00000E+01 9.98154E+00 2.28059E+00 −2.00000E+01 A4 = −1.98576E−02 −4.93972E−02 −1.97437E−01 −2.07642E−01 −8.69032E−02 A6 = 1.21634E−03 1.05901E−01 3.43247E−01 2.31853E−01 5.67844E−04 A8 = 3.83343E−02 1.46884E−01 −1.66052E−01 −2.27701E−01 4.69084E−02 A10 = −7.59112E−02 −3.06051E−01 −3.66354E−01 7.82506E−02 −4.08987E−02 A12 = 1.57766E−02 −4.48936E−01 4.29155E−01 −2.15686E−02 1.51424E−02 A14 = 3.22873E−02 8.52567E−01 −1.13058E−02 2.99640E−02 −4.60460E−03 Surface # 7 8 9 10 11 k = 1.69325E+01 −2.21184E+01 −3.85555E+00 −1.50109E+01 −1.45461E+01 A4 = −8.08105E−02 −7.26724E−02 −7.30420E−02 −3.56401E−02 −4.05237E−02 A6 = 2.16401E−02 2.91603E−02 3.85631E−02 3.39638E−03 5.53437E−03 A8 = −4.65644E−03 −1.78301E−02 −1.10840E−02 1.76931E−03 −8.43406E−04 A10 = 1.14028E−02 1.15181E−03 8.92508E−04 −2.08588E−04 2.36937E−05 A12 = −2.90845E−03 1.31575E−03 4.31774E−04 8.51982E−06 5.98748E−06 A14 = 5.57775E−05 2.11885E−04 −6.09681E−05 −2.28474E−06 2.55234E−07

The equation of the aspheric surface profiles of the fifth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the fifth embodiment are listed in the following TABLE 14.

TABLE 14 (Embodiment 5) f 4.42 (R9 + R10)/(R9 − R10) 0.03 Fno 3.00 R8/f −0.18 HFOV 32.6 f/f3 −0.09 V1 − V2 32.5 f/f5 −3.17 CT4/CT5 3.02 |f/f4| + |f/f5| 6.00 (T23 + T34)/CT3 2.27 SD/TD 0.82 (R3 + R4)/(R3 − R4) 2.47 TTL/ImgH 1.82 Embodiment 6

FIG. 6A shows an image capturing optical system in accordance with the sixth embodiment of the present invention, and FIG. 6B shows the aberration curves of the sixth embodiment of the present invention. The image capturing optical system of the sixth embodiment of the present invention mainly comprises five lens elements, in order from an object side to an image side:

a first lens element 610 made of plastic with positive refractive power having a convex object-side surface 611 and a concave image-side surface 612, the object-side and image-side surfaces 611 and 612 thereof being aspheric;

a second lens element 620 made of plastic with negative refractive power having a convex object-side surface 621 and a concave image-side surface 622, the object-side and image-side surfaces 621 and 622 thereof being aspheric;

a third lens element 630 made of plastic with negative refractive power having a convex object-side surface 631 and a concave image-side surface 632, the object-side and image-side surfaces 631 and 632 thereof being aspheric;

a fourth lens element 640 made of plastic with positive refractive power having a concave object-side surface 641 and a convex image-side surface 642, the object-side and image-side surfaces 641 and 642 thereof being aspheric; and

a fifth lens element 650 made of plastic with negative refractive power having a concave object-side surface 651 and a concave image-side surface 652, the object-side and image-side surfaces 651 and 652 thereof being aspheric, and at least one inflection point is formed on both the object-side surface 651 and the image-side surface 652 thereof;

wherein an aperture stop 600 is disposed between the first lens element 610 and the second lens element 620;

the image capturing optical system further comprises an IR filter 660 disposed between the image-side surface 652 of the fifth lens element 650 and an image plane 671, and the IR filter 660 is made of glass and has no influence on the focal length of the image capturing optical system; the image capturing optical system further comprises an image sensor 670 provided on the image plane 671.

The detailed optical data of the sixth embodiment is shown in TABLE 15, and the aspheric surface data is shown in TABLE 16, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view.

TABLE 15 (Embodiment 6) f = 4.44 mm, Fno = 3.00, HFOV = 32.5 deg. Focal Surface # Curvature Radius Thickness Material Index Abbe # length 0 Object Plano Infinity 1 Lens 1   1.804009 (ASP) 0.524 Plastic 1.544 55.9 3.36 2 113.600087 (ASP) 0.050 3 Ape. Stop Plano 0.050 4 Lens 2   6.346443 (ASP) 0.250 Plastic 1.634 23.8 -6.99 5   2.569306 (ASP) 0.560 6 Lens 3  10.272469 (ASP) 0.490 Plastic 1.634 23.8 -38.91 7   7.118337 (ASP) 0.470 8 Lens 4  -19.029392 (ASP) 0.916 Plastic 1.544 55.9 1.49 9   -0.792057 (ASP) 0.196 10 Lens 5   -1.484695 (ASP) 0.280 Plastic 1.544 55.9 -1.33 11    1.497125 (ASP) 0.500 12 IR-filter Plano 0.300 Glass 1.517 64.2 — 13 Plano 0.694 14 Image Plano — * Reference wavelength is d-line 587.6 nm

TABLE 16 Aspheric Coefficients Surface # 1 2 4 5 6 k = 8.60551E−01 5.00000E+01 1.18679E+00 2.85522E+00 −2.00000E+01 A4 = −1.60172E−02 −5.36724E−02 −2.05550E−01 −1.97878E−01 −8.89323E−02 A6 = 4.32136E−03 1.04231E−01 3.31699E−01 2.28309E−01 7.01936E−04 A8 = 3.77047E−02 1.51298E−01 −1.76025E−01 −2.45030E−01 4.74684E−02 A10 = −8.23865E−02 −3.29860E−01 −3.98970E−01 8.37582E−02 −4.18770E−02 A12 = 5.15429E−02 −4.43656E−01 4.29156E−01 −2.15686E−02 1.19403E−02 A14 = 8.10507E−04 8.52567E−01 −1.13058E−02 2.99640E−02 −4.60460E−03 Surface # 7 8 9 10 11 k = 1.62696E+01 −4.86804E+01 −3.91946E+00 −1.40110E+01 −1.56266E+01 A4 = −8.15130E−02 −7.19781E−02 −7.15261E−02 −3.56895E−02 −4.00646E−02 A6 = 2.12200E−02 2.87050E−02 3.81708E−02 3.40509E−03 5.48056E−03 A8 = −5.02386E−03 −1.82441E−02 −1.12650E−02 1.76919E−03 −8.33428E−04 A10 = 1.12441E−02 9.83787E−04 8.51052E−04 −2.07794E−04 2.44574E−05 A12 = −2.94916E−03 1.26479E−03 4.21388E−04 8.97288E−06 6.16287E−06 A14 = 5.57775E−05 2.08258E−04 −6.47436E−05 −2.16751E−06 2.93007E−07

The equation of the aspheric surface profiles of the sixth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the sixth embodiment are listed in the following TABLE 17.

TABLE 17 (Embodiment 6) f 4.44 (R9 + R10)/(R9 − R10) 0.00 Fno 3.00 R8/f −0.18 HFOV 32.5 f/f3 −0.11 V1 − V2 32.1 f/f5 −3.34 CT4/CT5 3.27 |f/f4| + |f/f5| 6.32 (T23 + T34)/CT3 2.10 SD/TD 0.85 (R3 + R4)/(R3 − R4) 2.36 TTL/ImgH 1.81 Embodiment 7

FIG. 7A shows an image capturing optical system in accordance with the seventh embodiment of the present invention, and FIG. 7B shows the aberration curves of the seventh embodiment of the present invention. The image capturing optical system of the seventh embodiment of the present invention mainly comprises five lens elements, in order from an object side to an image side:

a first lens element 710 made of plastic with positive refractive power having a convex object-side surface 711 and a concave image-side surface 712, the object-side and image-side surfaces 711 and 712 thereof being aspheric;

a second lens element 720 made of plastic with negative refractive power having a convex object-side surface 721 and a concave image-side surface 722, the object-side and image-side surfaces 721 and 722 thereof being aspheric;

a third lens element 730 made of plastic with positive refractive power having a concave object-side surface 731 and a convex image-side surface 732, the object-side and image-side surfaces 731 and 732 thereof being aspheric;

a fourth lens element 740 made of plastic with positive refractive power having a concave object-side surface 741 and a convex image-side surface 742, the object-side and image-side surfaces 741 and 742 thereof being aspheric; and

a fifth lens element 750 made of plastic with negative refractive power having a concave object-side surface 751 and a concave image-side surface 752, the object-side and image-side surfaces 751 and 752 thereof being aspheric, and at least one inflection point is formed on both the object-side surface 751 and the image-side surface 752 thereof;

wherein an aperture stop 700 is disposed between the first lens element 710 and the second lens element 720;

the image capturing optical system further comprises an IR filter 760 disposed between the image-side surface 752 of the fifth lens element 750 and an image plane 771, and the IR filter 760 is made of glass and has no influence on the focal length of the image capturing optical system; the image capturing optical system further comprises an image sensor 770 provided on the image plane 771.

The detailed optical data of the seventh embodiment is shown in TABLE 18, and the aspheric surface data is shown in TABLE 19, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view.

TABLE 18 (Embodiment 7) f = 4.20 mm, Fno = 2.85, HFOV = 34.5 deg. Focal Surface # Curvature Radius Thickness Material Index Abbe # length 0 Object Plano Infinity 1 Lens 1   1.700670 (ASP) 0.516 Plastic 1.544 55.9 3.64 2  10.680800 (ASP) 0.050 3 Ape. Stop Plano 0.064 4 Lens 2   2.979900 (ASP) 0.250 Plastic 1.634 23.8 -6.84 5   1.708630 (ASP) 0.513 6 Lens 3 -39.213400 (ASP) 0.401 Plastic 1.544 55.9 17.50 7  -7.690500 (ASP) 0.558 8 Lens 4  -9.964300 (ASP) 0.833 Plastic 1.544 55.9 1.65 9  -0.849920 (ASP) 0.228 10 Lens 5  -1.442450 (ASP) 0.280 Plastic 1.544 55.9 -1.39 11   1.698590 (ASP) 0.500 12 IR-filter Plano 0.300 Glass 1.517 64.2 — 13 Plano 0.558 14 Image Plano — * Reference wavelength is d-line 587.6 nm

TABLE 19 Aspheric Coefficients Surface # 1 2 4 5 6 k = 8.38613E−01 −3.05112E+01 −4.80408E−02 1.97799E+00 2.40506E+02 A4 = −1.43412E−02 −5.60888E−02 −2.09727E−01 −2.02496E−01 −7.56867E−02 A6 = −1.40300E−03 1.11809E−01 3.08044E−01 2.06654E−01 6.60201E−03 A8 = 3.72223E−02 7.93690E−02 −1.62791E−01 −2.44818E−01 5.55997E−02 A10 = −8.58912E−02 −1.95881E−01 −3.40311E−01 7.25977E−02 −3.25325E−02 A12 = 7.30630E−02 −4.32284E−01 4.45844E−01 −1.88031E−02 2.00380E−02 A14 = −6.77788E−03 8.63941E−01 −4.62315E−02 2.34562E−02 −4.60460E−03 Surface # 7 8 9 10 11 k = 6.36991E+00 1.89992E+01 −3.53695E+00 −9.95677E+00 −1.49360E+01 A4 = −8.52244E−02 −9.06096E−02 −7.76829E−02 −3.87547E−02 −4.05138E−02 A6 = 1.58712E−02 2.60126E−02 3.21903E−02 3.07689E−03 5.30551E−03 A8 = −7.58848E−03 −1.72042E−02 −1.20811E−02 1.70863E−03 −8.19341E−04 A10 = 1.21813E−02 1.10776E−03 9.08862E−04 −2.13987E−04 2.77001E−05 A12 = 5.95033E−04 9.73596E−04 5.18028E−04 8.87147E−06 5.35976E−06 A14 = 5.57775E−05 −2.66096E−04 −1.72111E−05 −1.59460E−06 −2.80410E−07

The equation of the aspheric surface profiles of the seventh embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the seventh embodiment are listed in the following TABLE 20.

TABLE 20 (Embodiment 7) f 4.20 (R9 + R10)/(R9 − R10) −0.08 Fno 2.85 R8/f −0.20 HFOV 34.5 f/f3 0.24 V1 − V2 32.1 f/f5 −3.02 CT4/CT5 2.98 |f/f4| + |f/f5| 5.56 (T23 + T34)/CT3 2.67 SD/TD 0.85 (R3 + R4)/(R3 − R4) 3.69 TTL/ImgH 1.73 Embodiment 8

FIG. 8A shows an image capturing optical system in accordance with the eighth embodiment of the present invention, and FIG. 8B shows the aberration curves of the eighth embodiment of the present invention. The image capturing optical system of the eighth embodiment of the present invention mainly comprises five lens elements, in order from an object side to an image side:

a first lens element 810 made of plastic with positive refractive power having a convex object-side surface 811 and a convex image-side surface 812, the object-side and image-side surfaces 811 and 812 thereof being aspheric;

a second lens element 820 made of plastic with negative refractive power having a concave object-side surface 821 and a concave image-side surface 822, the object-side and image-side surfaces 821 and 822 thereof being aspheric;

a third lens element 830 made of plastic with positive refractive power having a convex object-side surface 831 and a convex image-side surface 832, the object-side and image-side surfaces 831 and 832 thereof being aspheric;

a fourth lens element 840 made of plastic with positive refractive power having a concave object-side surface 841 and a convex image-side surface 842, the object-side and image-side surfaces 841 and 842 thereof being aspheric; and

a fifth lens element 850 made of plastic with negative refractive power having a concave object-side surface 851 and a concave image-side surface 852, the object-side and image-side surfaces 851 and 852 thereof being aspheric, and at least one inflection point is formed on both the object-side surface 851 and the image-side surface 852 thereof;

wherein an aperture stop 800 is disposed between the first lens element 810 and the second lens element 820;

the image capturing optical system further comprises an IR filter 860 disposed between the image-side surface 852 of the fifth lens element 850 and an image plane 871, and the IR filter 860 is made of glass and has no influence on the focal length of the image capturing optical system; the image capturing optical system further comprises an image sensor 870 provided on the image plane 871.

The detailed optical data of the eighth embodiment is shown in TABLE 21, and the aspheric surface data is shown in TABLE 22, wherein the units of the radius of curvature, the thickness and the focal length are expressed in mm, and HFOV is half of the maximal field of view.

TABLE 21 (Embodiment 8) f = 4.49 mm, Fno = 2.85, HFOV = 32.4 deg. Focal Surface # Curvature Radius Thickness Material Index Abbe # length 0 Object Plano Infinity 1 Lens 1  2.120513 (ASP) 0.514 Glass 1.548 45.7 2.99 2 -6.617692 (ASP) 0.050 3 Ape. Stop Plano 0.056 4 Lens 2 -28.901734 (ASP) 0.322 Plastic 1.634 23.8 -4.10 5   2.867103 (ASP) 0.571 6 Lens 3   5.937584 (ASP) 0.429 Plastic 1.544 55.9 8.36 7 -18.979522 (ASP) 0.873 8 Lens 4  -8.867389 (ASP) 0.973 Plastic 1.544 55.9 1.39 9  -0.724964 (ASP) 0.050 10 Lens 5  -1.861135 (ASP) 0.416 Plastic 1.535 56.3 -1.07 11   0.894534 (ASP) 0.550 12 IR-filter Plano 0.300 Glass 1.517 64.2 — 13 Plano 0.373 14 Image Plano — * Reference wavelength is d-line 587.6 nm

TABLE 22 Aspheric Coefficients Surface # 1 2 4 5 6 k = 7.09009E−01 −1.75995E+01 −5.00000E+01 4.44429E+00 −5.00000E+01 A4 = −1.28709E−02 −4.90738E−02 −1.53310E−01 −1.73256E−01 −7.59628E−02 A6 = −1.78431E−02 1.05440E−01 3.52326E−01 2.46889E−01 8.74262E−03 A8 = 2.85042E−03 −3.61364E−02 −3.32274E−01 −2.61516E−01 3.41803E−02 A10 = 1.64335E−02 −1.56180E−01 7.31004E−03 1.52674E−01 −4.19148E−02 A12 = −2.73584E−02 1.38384E−01 1.47237E−01 −7.44427E−02 4.02997E−02 A14 = −5.97038E−03 −3.21924E−02 −4.62316E−02 2.34564E−02 −1.25716E−02 Surface # 7 8 9 10 11 k = 2.00000E+01 −2.76431E+00 −4.67299E+00 −1.58711E+01 −9.19139E+00 A4 = −9.27772E−02 −9.25152E−02 −8.15721E−02 −6.30754E−02 −3.49447E−02 A6 = 2.61856E−02 1.82507E−02 2.64045E−02 4.17828E−03 6.33295E−03 A8 = −1.15699E−02 −2.46724E−02 −1.45054E−02 1.98755E−03 −9.16376E−04 A10 = 1.12377E−02 7.16742E−04 6.83661E−04 −1.95861E−04 1.47506E−05 A12 = 1.74124E−03 2.76746E−03 5.65811E−04 1.05854E−05 6.01923E−06 A14 = −1.53778E−04 −2.72596E−04 4.14326E−05 −9.30753E−07 −2.45432E−07

The equation of the aspheric surface profiles of the eighth embodiment has the same form as that of the first embodiment. Moreover, the description of the factors in the relations is as those set forth in the first embodiment, but the values of the relations of the eighth embodiment are listed in the following TABLE 23.

TABLE 23 (Embodiment 8) f 4.49 (R9 + R10)/(R9 − R10) 0.35 Fno 2.85 R8/f −0.16 HFOV 32.4 f/f3 0.54 V1 − V2 21.9 f/f5 −4.18 CT4/CT5 2.34 |f/f4| + |f/f5| 7.41 (T23 + T34)/CT3 3.36 SD/TD 0.87 (R3 + R4)/(R3 − R4) 0.82 TTL/ImgH 1.88

It is to be noted that TABLES 1-23 show different data of the different embodiments, however, the data of the different embodiments are obtained from experiments. Therefore, any image capturing optical system of the same structure is considered to be within the scope of the present invention even if it uses different data. The embodiments depicted above and the appended drawings are exemplary and are not intended to limit the scope of the present invention. 

What is claimed is:
 1. An image capturing optical system comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element; a third lens element; a fourth lens element with both the object-side and image-side surfaces thereof being aspheric, and the fourth lens element is made of plastic; and a fifth lens element with negative refractive power, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof, and the fifth lens element is made of plastic; wherein a focal length of the image capturing optical system is f, a focal length of the fifth lens element is f5, and they satisfy the following relation: −5.0<f/f5<−3.0.
 2. The image capturing optical system according to claim 1, wherein the fifth lens element has a concave image-side surface.
 3. The image capturing optical system according to claim 2, wherein the second lens element has negative refractive power and the fifth lens element has a concave object-side surface.
 4. The image capturing optical system according to claim 3, wherein a curvature radius of the object-side surface of the second lens element is R3, a curvature radius of the image-side surface of the second lens element is R4, and they satisfy the following relation: 1.5<(R3+R4)/(R3−R4)<4.5.
 5. The image capturing optical system according to claim 3, wherein the fourth lens element has positive refractive power and has a convex image-side surface, the focal length of the image capturing optical system is f, a focal length of the third lens element is f3, and they satisfy the following relation: −0.5<f/f3<0.5.
 6. The image capturing optical system according to claim 5, wherein a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, and they satisfy the following relation: 2.5<CT4/CT5<4.5.
 7. The image capturing optical system according to claim 5, wherein a curvature radius of the image-side surface of the fourth lens element is R8, the focal length of the image capturing optical system is f, and they satisfy the following relation: −0.25<R8/f<−0.05.
 8. The image capturing optical system according to claim 2, further comprising a stop, an axial distance between the stop and the image-side surface of the fifth lens element is SD, an axial distance between the object-side surface of the first lens element and the image-side surface of the fifth lens element is TD, and they satisfy the following relation: 0.75<SD/TD<1.1.
 9. The image capturing optical system according to claim 8, further comprising an image sensor provided on an image plane, an axial distance between the second lens element and the third lens element is T23, an axial distance between the third lens element and the fourth lens element is T34, a central thickness of the third lens element is CT3, an axial distance between the object-side surface of the first lens element and the image plane is TTL, half of a diagonal length of an effective photosensitive area of the image sensor is ImgH, and they satisfy the following relations: 2.0<(T23+T34)/CT3<4.0; and TTL/ImgH<2.0.
 10. The image capturing optical system according to claim 8, wherein an Abbe number of the first lens element is V1, an Abbe number of the second lens element is V2, and they satisfy the following relation: 30<V1−V2<42.
 11. The image capturing optical system according to claim 1, wherein the second lens element has negative refractive power, and the fourth lens element has positive refractive power.
 12. The image capturing optical system according to claim 11, wherein the focal length of the image capturing optical system is f, the focal length of the fifth lens element is f5, and they satisfy the following relation: −4.5<f/f5<−3.2.
 13. The image capturing optical system according to claim 12, further comprising an image sensor provided on an image plane, an axial distance between the object-side surface of the first lens element and the image plane is TTL, half of a diagonal length of an effective photosensitive area of the image sensor is ImgH, and they satisfy the following relation: TTL/ImgH<2.0.
 14. The image capturing optical system according to claim 12, wherein the focal length of the image capturing optical system is f, the focal length of the fifth lens element is f5, and they satisfy the following relation: −4.5<f/f5<−3.4.
 15. The image capturing optical system according to claim 11, wherein the fourth lens element has a convex image-side surface, and the object-side surfaces and image-side surfaces of the first lens element, the second lens element and the third lens element are all aspheric.
 16. The image capturing optical system according to claim 15, wherein the second lens element has a convex object-side surface and a concave image-side surface; the fourth lens element has a concave object-side surface; and the fifth lens element has a concave object-side surface and a concave image-side surface.
 17. The image capturing optical system according to claim 15, wherein the first lens element, the second lens element and the third lens element are made of plastic, the focal length of the image capturing optical system is f, a focal length of the fourth lens element is f4, the focal length of the fifth lens element is f5, and they satisfy the following relation: 5.0<|f/f4|+|f/f5|<8.0.
 18. The image capturing optical system according to claim 15, wherein a curvature radius of the object-side surface of the fifth lens element is R9, a curvature radius of the image-side surface of the fifth lens element is R10, and they satisfy the following relation: −0.8<(R9+R10)/(R9−R10)<0.4.
 19. The image capturing optical system according to claim 15, wherein a curvature radius of the image-side surface of the fourth lens element is R8, the focal length of the image capturing optical system is f, and they satisfy the following relation: −0.25<R8/f<−0.05.
 20. The image capturing optical system according to claim 19, wherein a central thickness of the fourth lens element is CT4, a central thickness of the fifth lens element is CT5, and they satisfy the following relation: 2.5<CT4/CT5<4.5.
 21. An image capturing optical system comprising, in order from an object side to an image side: a first lens element with positive refractive power having a convex object-side surface; a second lens element with negative refractive power; a third lens element; a fourth lens element with positive refractive power, a convex image-side surface, both the object-side and image-side surfaces thereof being aspheric, and the fourth lens element is made of plastic; and a fifth lens element with negative refractive power, a concave image-side surface, both the object-side and image-side surfaces thereof being aspheric, at least one inflection point is formed on at least one of the object-side and image-side surfaces thereof, and the fifth lens element is made of plastic; wherein a focal length of the image capturing optical system is f, a focal length of the fifth lens element is f5, and they satisfy the following relation: −5.0<f/f5<−3.0.
 22. The image capturing optical system according to claim 21, wherein a curvature radius of the image-side surface of the fourth lens element is R8, the focal length of the image capturing optical system is f, and they satisfy the following relation: −0.25<R8/f<−0.05.
 23. The image capturing optical system according to claim 22, wherein the first lens element, the second lens element and the third lens element are made of plastic, the focal length of the image capturing optical system is f, a focal length of the fourth lens element is f4, the focal length of the fifth lens element is f5, and they satisfy the following relation: 5.0<|f/f4|+|f/f5|<8.0.
 24. The image capturing optical system according to claim 22, wherein the focal length of the image capturing optical system is f, the focal length of the fifth lens element is f5, and they satisfy the following relation: −4.5<f/f5<−3.2. 